HAT-P-11, also designated GSC 03561-02092, is an orange dwarf metal rich

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

about 123 light-years away in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Cygnus. This star is notable for its relatively large rate of

proper motion Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more dista ...

. The magnitude of this star is about 9, which means it is not visible to the

naked eye Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying, light-collecting optical instrument, such as a telescope or microscope, or eye protection. Vision corrected to normal ...

but can be seen with a medium-sized

amateur telescope ''Amateur Telescope Making'' (''ATM'') is a series of three books edited by Albert G. Ingalls between 1926 and 1953 while he was an associate editor at ''Scientific American''. The books cover various aspects of telescope construction and observ ...

on a clear dark night. The age of this star is about 6.5 billion years. The star has active latitudes that generate starspots. The star appears to have a very small radius, which can be explained by the anomalously high helium fraction.

Planetary system

An extrasolar planet, was discovered by the

HATNet Project The Hungarian Automated Telescope Network (HATNet) project is a network of six small fully automated "HAT" telescopes. The scientific goal of the project is to detect and characterize extrasolar planets using the transit method. This network is use ...

using the transit method, believed to be a little larger than the planet

Neptune Neptune is the eighth planet from the Sun and the farthest known planet in the Solar System. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times ...

. That planet orbits out of alignment from the star's spin axis. The system is oblique at 100°. This star system was within the field of view of the Kepler Mission planet-hunter

spacecraft A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, p ...

. A trend in the

radial velocity The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the temporal rate of change, rate of change of the distance or Slant range, range between the two points. It is e ...

measurements taken to confirm the planet indicated a possible additional body in the system. This was confirmed in 2018 when a second planet was detected on an approximately nine year orbit. In 2020, the true mass of HAT-P-11c was measured via

astrometry Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, the Milky Way. His ...

, along with

Pi Mensae b Pi Mensae b (π Men b, π Mensae b), also known as HD 39091 b, is an extrasolar planet approximately 59 light-years away in the constellation of Mensa. The planet was announced orbiting the yellow main-sequence star Pi Mensae in October 2001. ...

References

External links

* {{Stars of Cygnus Cygnus (constellation) K-type main-sequence stars Planetary transit variables Planetary systems with two confirmed planets 3 097657 Durchmusterung objects

Planetary system

See also

References

External links